(a) Field of the Invention
The present invention relates to a process for producing liquid crystal optical devices, particularly, to an efficient and economical process for continuously producing liquid crystal optical devices of high quality, which liquid crystal optical devices may be suitably used for display devices and memory devices using liquid crystals, especially for liquid crystal display devices which may be suitably used for display of moving pictures due to their excellent response property to external factors, and may as well be suitably used as of various shapes, such as those having a large picture plane or curved picture plane.
(b) Description of the Related Art
There have been made attempts to produce liquid crystal optical devices by using flexible substrates in order to obtain liquid crystal optical devices having such a good forming processability that they may be easily formed into large picture planes, curved picture planes, or the like. For example, Japanese Patent Application Laid-open No. 62-267720 discloses a method of using a plastic substrate as one side of the substrates and spreading a low molecular weight liquid crystal from a slit nozzle on the plastic substrate followed by adhering them by pressure using a pressure roller. Japanese Patent Application Laid-open No. 62-227122 discloses another method of applying a mesogenic side chain liquid-crystalline polymer to a substrate followed by carrying out shear orientation.
The method described in Japanese Patent Application Laid-open No. 62-267720, however, has disadvantages in that the use of the slit nozzle makes it difficult to uniformalize the outflow of the liquid crystal with the result that the excessive liquid crystal is pushed aside toward the adhesive layer at the time of pressing, and that because the method is carried out in a vacuum chamber, the complicated pressure adjusting is inevitable each time the substrate is carried in or out. The method described in Japanese Patent Application Laid-open No. 62-227122 also has serious problems. That is, the productivity is poor because each of the operations of coating of the liquid crystal, application of shear, etc. is conducted in batch system; owing to insufficient consideration of the stage for laminating the other substrate, incorporation of bubbles and disturbance of orientation tend to occur in the stage; and liquid crystal display devices having high speed response property cannot be obtained because ferroelectric liquid-crystalline polymer is not employed.
Therefore, in the industry manufacturing liquid crystal optical devices, there still remains a great problem that an easy and efficient process should be developed for producing liquid crystal optical devices having good forming processability and excellent fundamental properties, such as high speed response property.